1. Field of the Invention
The present invention relates to the field of conveying individual bins from a loading station to a bin-unloading station, and thereafter conveying the bins to a removing station.
2. Description of the Background Art
Automobile assembly lines are stocked with automobile parts contained in parts bins. The parts bins are loaded at the parts source and shipped in the bins to the automobile assembly plant. Typically, the bins are manufactured with runners along their bottom portions.
Previously, parts bins were moved to the assembly line using gravity. The full bins were brought in on an upper transport lane and lowered to a bottom level to the assembly line workers for emptying. Other methods for conveying the bins were later developed. According to one method, bins were gravity fed to the assembly line along a bottom lane rather than a top lane as described above. A major problem with gravity feed of parts bins involves the condition of the runners on the bottom of the bins. Extensive use in shipping and lack of concern as to their condition often results in broken, twisted or occasionally missing rails. Bins having damaged rails do not move smoothly on a gravity conveyor system. Consequently, gravity fed units frequently need to be adjusted to high pitch levels so that damaged bins will proceed. However, excessively high pitch levels accelerate undamaged bins to undesirable speeds.
Non-gravity fed conveyors of automobile parts bins are also known. These conveyors move the bins on rollers using a "pusher-dog." Although eliminating the necessity of using gravity to convey the bins, problems still may occur with damaged runners interfering with the rotation of the rollers on which the bins are conveyed. There remains a need in the art for an apparatus for conveying parts bins which does not possess the disadvantages of the prior art conveyors.